1. Field of the Invention
This invention relates generally to sheet feeding apparatus, and more specifically to a card injecting apparatus for inserting a card underneath a stack of flat articles.
2. Description of the Prior Art
It is generally well known in the art to provide apparatus for inserting marking strips or cards into a forming stack of flat articles. Exemplary patents illustrating such apparatus are U.S. Pat. Nos. 3,095,193, 3,205,739 and 3,458,186. In such apparatus, a separating device is moved over the upper article of a stack for separating the stack from the articles accumulating on the upper surface of the separating device. While so separated, a marking strip is fed between the upper article in the stack and the separating device. When the separating device is retracted, the articles that had accumulated on the separating device are added to the stack above the marking strip. Although such separating devices operate successfully for inserting marking strips into a forming stack of articles, it is highly unlikely that such devices could be used successfully for inserting a strip or card beneath a previously formed stack of articles without binding on the lowermost article. Another disadvantage of such prior known strip inserting apparatus is that the use of a reciprocally movable separating device is required, and such device during its reciprocal movement engages and marks adjacent articles which must then be removed and discarded. In addition, the operation of the reciprocally movable separating device misaligns the upper and lower stack of articles which must then be rearranged in proper alignment. It is also known in the prior art to inject air between the separating device and the adjacent article of a stack for separating the two to permit easy insertion and withdrawal of the separating device. However, the compressed air does not completely eliminate all contact between the separating device and adjacent articles, and the resultant friction makes it difficult to insert the retract the separating device. Still another disadvantage of such prior art strip inserting apparatus is that the apparatus contains a considerable number of moving parts, is of relatively complicated construction and hence relatively costly to manufacture.